In Conan, people have a brain option system.

Chapter 164 Technique (22)

Everyone in the room looked in the direction where the sound came from.

Then we saw that Genta Kojima found a Kamen Rider mask from somewhere and even put it on his own head.

Wearing the Kamen Rider mask, Genta Kojima seemed to have transformed himself into Kamen Rider, shouting excitedly.

"Hey, Yuan Taijun, put it down quickly! This may be important evidence!"

Dr. Agasa was startled and hurried forward, wanting to ask Genta Kojima to take off the hood.

However, just as Dr. Agasa came to Kojima Genta's side,

Then I saw Kojima Genta, who was wearing the Kamen Rider mask, his fat body swayed twice and fell to the ground as if he was drunk.

"Genta!"

Conan and Haibara Ai screamed and rushed to Kojima Genta's side.

Haibara Ai pulled off the Kamen Rider mask on Kojima Genta's head and found that Kojima Genta was already a little dazed and looked weak all over.

She reached out and opened Kojima Genta's eyes, and saw that Kojima Genta's eyes were red and even had tears in them.

"There's hydrogen sulfide in this hood!"

Haibara Ai recognized at a glance that Kojima Genta was showing symptoms of hydrogen sulfide poisoning.

The detectives who heard Huibara Ai's shout were also startled.
A policeman quickly took the detector and put it inside the mask of Kamen Rider to test the concentration of hydrogen sulfide inside the mask.

The test result is [90ppm], which is 0.009%.

For hydrogen sulfide, this concentration is enough to cause poisoning symptoms such as dizziness and nausea.

And because Kojima Genta is a child, this concentration of hydrogen sulfide caused him to fall into a coma in a short period of time.

"Fortunately, the concentration of hydrogen sulfide is not too high. Yuan Tai probably inhaled too much in a short period of time and fell into a coma."

Huihara Ai breathed a sigh of relief and said softly.

Conan looked at the mask of the Kamen Rider and finally figured out one of the suspicious points in this case.

"According to our original idea, the murderer must have produced hydrogen sulfide gas in Kenji Furusawa's room."

"But since the gas evaporates, it is very strange that there is no hydrogen sulfide gas in the air at the murder scene."

"But, if you just want to kill one person, there is no need to produce a lot of hydrogen sulfide gas."

"The murderer only needs to make hydrogen sulfide gas in an airtight leather hood, then put the hood on Kenji Furusawa's head, and then block the ventilation holes to kill with a small amount of hydrogen sulfide gas!"

"This way, even if a little bit of hydrogen sulfide gas is released, it won't have a big impact on the air in the room."

Conan immediately understood the murderer's method of killing.

"Then, what remains is the murderer's method of making hydrogen sulfide."

Although Kojima Genta only fell into a coma for a short time, the detective still called an ambulance just in case.

At the same time, the police from the Forensic Department took away the Kamen Rider mask that the murderer used to make hydrogen sulfide and served as a container.

"Can you detect how hydrogen sulfide is produced?"

Conan asked Haibara Ai in a low voice.

"It may be possible to find the ingredients before the reaction, but if you want to determine what it came from, it will probably take quite a long time."

Huihara Ai answered.

After a brief exchange of views with Haibara Ai, Conan went to check the rooms of Motoki Mayumi and Matsutani Jōichi.

Then they found out that Matsutani Jōichi's suitcase was not very big, and there were quite a lot of luggage inside, which was obviously not enough to hide the black suitcase used to dump the body.

Mayumi Motoki has a rather large suitcase, which is large enough to fit a smaller suitcase.

Originally, in the judgment of Conan and most of the detectives present, Mayumi Motoki, as the first discoverer, was not a big suspect.

Because Mayumi Motoki is a woman who does not look strong, it is obviously not easy for her to complete the process of killing and disposing of the body alone.

But after they heard Akikawa Sosuke say that Motoki Mayumi and Matsutani Jōichi had privately discussed killing Furusawa Kenji,

I started to think that Motoki Mayumi and Matsutani Jōichi collaborated to carry out this murder.

In this case, Mayumi Motoki is highly suspected.

only.

After searching the two people's room and luggage, the police also did not find any suspicious chemicals.

"Could it be that when the murderer discarded the suitcase, he also threw away the materials used to make hydrogen sulfide?"

"Or maybe they just brought enough for the reaction and used it all up when making the hydrogen sulfide gas?"

The inspector of Kanagawa Prefectural Police Headquarters asked Dr. Agasa.

"Even if we happen to run out of it, we still need a container for the substance containing hydrogen sulfide, and a container for the 'acid' used for the reaction."

"Besides, I don't think they can control the dosage so precisely."

Huihara Ai gave the answer.

So Conan followed Haibara Ai and carefully checked the rooms of Motoki Mayumi and Matsutani Jōichi again.

Then Conan discovered that the bathtub in Matsutani Choichi's room showed signs of having been used.

In Jōichi Matsutani's luggage, Conan also found some used bath additives.

It is not uncommon for Japanese people to use bath additives when taking a bath.

But the problem is that the bathing gel used by Matsutani Choichi is the hot spring hotel's own brand of bathing gel sold by Kosenan.

The characteristic of this bath additive is that it can perfectly reproduce the hot spring of Kosenan.

This immediately aroused Conan's suspicion.

"We checked into the hot spring hotel, but Matsutani Choichi wanted to take a bath in the room."

"Forget about taking a bath. He even used Kosenan's bathing powder."

'In that case, why doesn't he just go to the hot spring downstairs and take a bath?'

"No matter how you think about it, the real thing is much better than the fake hot spring made with bath additives, right?"

"Unless, his purpose was not to take a bath at all, but to use the bath additive for other purposes."

Conan thought about this in his mind, and hurriedly confirmed the ingredients of Kosenan's bath powder.

Sure enough, Conan soon found magnesium sulfide in the ingredient list of Kosenan's bath powder.

Magnesium sulfide is used in bath preparations, usually to provide a mineral and foaming effect.
In order to better restore the feeling of natural hot springs.

"Habara, this!"

"Ah."

Haibara Ai stared at the ingredient list of the Kosenan bath spray in her hand and nodded solemnly.

(End of this chapter)